1 //===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the PHITransAddr class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_PHITRANSADDR_H
15 #define LLVM_ANALYSIS_PHITRANSADDR_H
17 #include "llvm/Instruction.h"
18 #include "llvm/ADT/SmallVector.h"
24 /// PHITransAddr - An address value which tracks and handles phi translation.
25 /// As we walk "up" the CFG through predecessors, we need to ensure that the
26 /// address we're tracking is kept up to date. For example, if we're analyzing
27 /// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
28 /// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
29 /// incorrect pointer in the predecessor block.
31 /// This is designed to be a relatively small object that lives on the stack and
35 /// Addr - The actual address we're analyzing.
38 /// TD - The target data we are playing with if known, otherwise null.
41 /// InstInputs - The inputs for our symbolic address.
42 SmallVector<Instruction*, 4> InstInputs;
44 PHITransAddr(Value *addr, const TargetData *td) : Addr(addr), TD(td) {
45 // If the address is an instruction, the whole thing is considered an input.
46 if (Instruction *I = dyn_cast<Instruction>(Addr))
47 InstInputs.push_back(I);
50 Value *getAddr() const { return Addr; }
52 /// NeedsPHITranslationFromBlock - Return true if moving from the specified
53 /// BasicBlock to its predecessors requires PHI translation.
54 bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
55 // We do need translation if one of our input instructions is defined in
57 for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
58 if (InstInputs[i]->getParent() == BB)
63 /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
64 /// if we have some hope of doing it. This should be used as a filter to
65 /// avoid calling PHITranslateValue in hopeless situations.
66 bool IsPotentiallyPHITranslatable() const;
68 /// PHITranslateValue - PHI translate the current address up the CFG from
69 /// CurBB to Pred, updating our state to reflect any needed changes. If the
70 /// dominator tree DT is non-null, the translated value must dominate
71 /// PredBB. This returns true on failure and sets Addr to null.
72 bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB,
73 const DominatorTree *DT);
75 /// PHITranslateWithInsertion - PHI translate this value into the specified
76 /// predecessor block, inserting a computation of the value if it is
79 /// All newly created instructions are added to the NewInsts list. This
80 /// returns null on failure.
82 Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
83 const DominatorTree &DT,
84 SmallVectorImpl<Instruction*> &NewInsts);
88 /// Verify - Check internal consistency of this data structure. If the
89 /// structure is valid, it returns true. If invalid, it prints errors and
93 Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB,
94 const DominatorTree *DT);
96 /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
97 /// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
98 /// block. All newly created instructions are added to the NewInsts list.
99 /// This returns null on failure.
101 Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
102 BasicBlock *PredBB, const DominatorTree &DT,
103 SmallVectorImpl<Instruction*> &NewInsts);
105 /// AddAsInput - If the specified value is an instruction, add it as an input.
106 Value *AddAsInput(Value *V) {
107 // If V is an instruction, it is now an input.
108 if (Instruction *VI = dyn_cast<Instruction>(V))
109 InstInputs.push_back(VI);
115 } // end namespace llvm